In numerous industries, such as the aviation or aerospace industries, in order to minimize costs and reduce development times (prototyping, testing), it is common practice to make use of virtual representations of an article that is to be designed. Such modeling presents the advantage of penalizing work little (in terms of cost and time) in the event of any backtracking during design. Modeling the article in virtual reality also makes it possible to perform all kinds of simulations that are useful for validating the design thereof.
Nevertheless, modeling and simulation are not restricted to designing articles. They can also be used for simulating human actions in a defined environment in order to visualize the movements and the postures that a technician will need to perform in order to effect particular actions. This is useful for validating and optimizing accessibility to certain parts of a piece of equipment that require regular inspection and maintenance, such as parts in an airplane engine, for example. Thus, ease of access to various elements of a piece of equipment can be verified virtually as soon as the equipment has been modelled, with this being made possible by simulation using a virtual dummy.
Virtual dummies are already in use for this type of application, as with software such as the Catia (trademark) software from Dassault Systems. That software enables simulations to be performed using a virtual dummy which is animated by manipulating its members and by acting on the degrees of freedom associated with each member. In order to obtain realistic simulation from a virtual dummy, it is necessary to ensure that the movements of each member are performed in compliance with the degrees of freedom that are associated with the member in question. In addition, depending on the surroundings (obstacles, position of the dummy, proximity of hazards for the operator), the degrees of freedom can be further limited. It must then be possible to block/unblock members or certain degrees of freedom thereof in order to obtain a simulation that takes account of the surroundings.
In that solution, the operations of manipulating a member or blocking/deblocking degrees of freedom of the member take place degree by degree. In other words, for each degree of freedom, the degree is selected or edited by means of a number, and then a decision is taken either to block it or to manipulate it. Such a procedure is relatively lengthy and fiddly. It is restricted to a single degree of freedom at a time while manipulating actions directly. Furthermore, it is necessary to know the number of each degree of freedom for each joint, and that does not make it easy to control the parameterization of the dummy.